step(umc2,ps,tm(s,[ctxm(alpha_2_1_,umc,ip, (ip,umc2), (ip,umc2)),ctxm(alpha_2_1_,ps,ip, (ip,ps), (ip,ps))],pri(lst,[ctxm(alpha_2_1_,u,bsn,i_bsn,i_bsn),ctxm(alpha_2_1_,umc,dom, (dom,umc2), (dom,umc2))]))).